# HALOWERK Land Compare – Topsoil pH Multi-Site Ranking

> HALOWERK Land Compare – Topsoil pH Multi-Site Ranking is a paid API for AI agents from landvergleich.halowerk.com, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-13).

Measures topsoil pH for 2–10 named European sites specified by WGS84 coordinates and returns a ranked list of sites by pH value with ties preserved.

## Facts

- Endpoint: POST https://landvergleich.halowerk.com/v1/rank-sites-soil-ph
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-land-compare-topsoil-ph-multi-site-ranking-484ad1ca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4qbZeM-lQ6AV3YVwlBuc0

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability halowerk-land-compare-topsoil-ph-multi-site-ranking-484ad1ca -d '<json body>'
```

Example prompt: Can you rank these five farm sites by topsoil pH — site A at 51.5°N, 4.2°E; site B at 48.8°N, 2.3°E; site C at 52.4°N, 13.4°E; site D at 40.4°N, -3.7°E; and site E at 45.4°N, 12.3°E — from most acidic to least?

## When to prefer this

Use this endpoint when you need to compare and rank topsoil pH across multiple (2–10) European locations simultaneously, rather than comparing exactly two sites or fetching a single site's pH. It is the right choice when the goal is a ranked ordering with tie handling, such as for land scouting, agricultural site selection, or environmental assessments across European coordinates.

## Known failure modes

- Coordinates outside the European coverage area (lat 34–72.5°N, lon -31.5–40.5°E) will result in an error or missing data
- Fewer than 2 or more than 10 locations provided will fail input validation
- Missing required latitude or longitude fields for any location will cause a validation error
- Unavailable soil data for a specific coordinate may result in null pH values for that site
- Payment failure or insufficient USDC balance may block the request

## How this service works

Measures topsoil ph for two to ten named European sites and ranks the observed values with ties preserved.

## Output

Returns a ranked list of the submitted sites ordered by their measured topsoil pH values, with ties preserved, including the pH reading for each named site. Allows direct comparison of soil acidity across up to ten European locations in a single call.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "locations": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "longitude",
     "latitude"
    ],
    "properties": {
     "name": {
      "type": "string",
      "maxLength": 60,
      "minLength": 1
     },
     "latitude": {
      "type": "number",
      "maximum": 72.5,
      "minimum": 34,
      "description": "WGS84 latitude inside the published European coverage."
     },
     "longitude": {
      "type": "number",
      "maximum": 40.5,
      "minimum": -31.5,
      "description": "WGS84 longitude inside the published European coverage."
     }
    },
    "additionalProperties": false
   },
   "maxItems": 10,
   "minItems": 2
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-land-compare-topsoil-ph-multi-site-ranking-484ad1ca/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from landvergleich.halowerk.com](https://www.zero.xyz/host/landvergleich.halowerk.com/llms.txt)